1. Technical Field
In general, the present invention provides a particle size breakup apparatus. More particularly, the present invention relates to a mixer that implements the particle size breakup apparatus and includes a stator having a plurality of openings formed thereon and a rotor disposed inwardly of the stator and spaced away from the stator with a specific gap, that is, the so-called rotor/stator type mixer.
2. Description of the Prior Art
Generally, it is shown in FIG. 1 that the so-called rotor/stator type mixer comprises a mixer unit 4 that includes a stator 2 having a plurality of openings 1 formed thereon and a rotor 3 disposed inwardly of the stator 2 and spaced away from the stator 2 with a specific gap δ. This so-called rotor/stator type mixer provides the emulsifying, dispersing, particle size breaking up, mixing and any other processing facilities for a fluid or liquid (referred to hereinafter as “fluid) being processed, by taking advantage of the high shearing stress that may be produced in the neighborhood of the gap between the rotor 3 rotating at high speeds and the stator 2 in its fixed position, and may be widely used for mixing and preparing the fluid or liquid being processed in the manufacturing fields such as the foods, pharmaceutical medicines, chemical products and other like industries.
The rotor/stator type mixer may be divided into the two classes, such as the external circulation mode mixer that allows the fluid being processed to circulate as indicated by an arrow 5a in FIG. 2 and the internal circulation mode mixer that allows the fluid being processed to circulate as indicated by an arrow 5b in FIG. 2.
The rotor/stator type mixer is now available in the various forms and circulation modes. For example, the Patent Document 1 (the apparatus for and method of producing particles using the combination of the rotor and stator) proposes an apparatus for and method of producing particle sizes that may be applied to produce those particles, in which the mixer includes the stator having a plurality of openings formed thereon and the rotor disposed inwardly of the stator and spaced away from the stator with a specific gap, and may be widely used for manufacturing the pharmaceutical medicines, nutritious supplement foods, chemical products, cosmetics and the like. It is described that the mixer can be scaled up in the effective, simple and easy manner.
There are several indexes (theories) that have been reported heretofore as the methods for estimating the performances for the mixers of the various forms and types.
For example, when the attention is focused on the liquid-to-liquid dispersion operation as well as the rotor/stator type mixer discussed above, it is reported that the sizes for the resulting liquid drop diameters can be discussed in terms of the calculated values (greater or smaller) for the average energy dissipation rate (Non-Patent Documents 1 and 2), but it is not apparent from those Non-Patent documents 1 and 2 that the method for calculating the average energy dissipation rate is available.
There are several reports that describe the study cases in which the experiment results have been arranged so that those experiment results can be applied to individual misers (Non-Patent Documents 3 to 6). In those study cases (Non-Patent Documents 3 to 6), however, the particle size breakup effect for the mixer has only been discussed in terms of the effect of the gap on the rotor and stator, the effect of the openings (holes) on the stator, and the like. What has been reported in those study cases is different for each individual mixer.
There are also several reports that describe the study cases in which the particle size breakup mechanism for the rotor/stator type mixer is discussed (Non-Patent Documents 7 and 8). It is suggested in those documents that the particle size breakup effect for the resulting liquid drop diameters may be promoted by the energy dissipation rate for the turbulent flow and may be affected by the frequency with which the liquid being processed is subjected to the shearing stress (shearing frequency).
For the scale-up method for the rotor/stator type mixer, there are several reports in which the final resulting liquid drop diameters (the most stable resulting liquid drop diameters) that can be obtained by running the mixer for a long time are discussed (Non-Patent Document 9). However, the scale-up method is not practical on the actual manufacturing plants, and so it is not useful. Even if it is assumed that the mixer's processing time is considered and the resulting liquid drop diameters are estimated, what is reported is only the phenomena (facts) that are simply based on the actually measured values (experiment values). The report does not describe the study case in which the resulting liquid drop diameters are analyzed theoretically.
Although the Patent Document 1 mentioned above describes the superiority (performance) of a particular type mixer and presents the numerical value ranges for designing such particular type mixer, the numerical ranges for designing the high performance mixer and the theoretical grounds on which the numerical value ranges are based are not described specifically. The information on the types and forms of the high performance mixer is not disclosed.
As described above, several indexes (theories) that provide the basis for the performance estimation method for the mixers of the various types or forms have been reported. It should be noted, however, that in many cases, those indexes can only be applied to the individual mixers of the same type or form. In most cases, actually, those indexes cannot be applied to the various type mixers each having a different form. For example, although there may be indexes that can only be applied to those mixers in which the gap between the rotor and the stator has a great effect on the particle size breakup or there may be indexes that can only be applied to those mixers in which the openings (holes) formed on the stator have a great effect on the resulting particle size breakup, the comprehensive indexes that can be applied to all of the mixers of all possible types or forms have not been discussed, and it is not considered that the indexes can be applied to all of the mixers of all possible types or forms.
It may be apparent from the above description that there are no study cases in which the performance estimation method and the scale-up method for the rotor/stator type mixers have been discussed. In addition, there are no study cases in which the indexes that can be applied to all of the various type mixers each having a different form have been discussed and in which the experiment results that are thus obtained have been arranged in any appropriate order.
In the prior art and in most cases, the performance estimation method and the scale-up method for the rotor/stator type mixers are estimated (1) for each individual mixer, (2) by using the small-scale machine, (3) for the resulting liquid drop diameters (most stable resulting liquid drop diameters) obtained during the long running time. In other words, it should be noted that in the prior art, the resulting liquid drop diameters that can be obtained (A) for the various type mixers and (B) by employing the large-scale machine (on the actual manufacturing installation) (C) during the mixer's particular running time have not been evaluated nor estimated.
For example, although it may be admitted that there are the indexes that can only be applied to those mixers for which the size of the gap between the rotor and the stator has a great effect on the resulting particle size breakup or emulsification, or there are the indexes that can only be applied to those mixers for which the size or form of each of the openings (holes) formed on the stator has a great effect on the resulting particle size breakup or emulsification, the comprehensive indexes that can be applied to all of the mixers of all possible types and forms (the theories on which the various type mixers can be compared or estimated comprehensively or in the unified manner) were not discussed, and there were no indexes that consider the above comparison or estimation.
For the above reason, the mixers were actually estimated regarding their respective performances and designed (developed and fabricated accordingly while the mixers were being tested on the trial and error basis by using the actual fluid being processed.